SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbac7c6b0bd85cb0fe06475a43cf0a2616aca8c90d7cdcc2e8292d21495a9f90' 
  AND token = 'Mlj+vxmmn2LlNBstGKneZfOL27bU/BOrhKhjlqKwkLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}